REPRODUCTION OF AN AURAL TEXT P01TORMANΠSTAGE

The objective of this trial was to determine whether an experimental xylanase enzyme (ABO374) product had the potential to increase broiler performance on a maize based diet with soybean meal being the main protein source. The experimental xylanase enzyme (ABO374) product was also compared to a commercial xylanase enzyme product.

The results obtained during this performance trial gives a clear indication that the use of exogenous fibrolytic enzymes, especially xylanase, in a commercial maize - soybean broiler diet can improve broiler performance. The experimental xylanase enzyme ABO374 outperformed the commercial enzyme when it was added at 2671mL/ton with a xylanase activity of 1426.86nkat/mL. With the starter feed FCR and the overall FCR being significantly (P<0.05) improved by the application of ABO374 to the feed, it is possible to reduce the amount of feed being used for production and therefore reducing the production cost per bird. One of the possible reasons stated in the discussion why the FCR for the grower and finisher period did not improve when the diet was supplemented ABO374, is that the enzyme could have inactivated during pelleting, the ABO374 enzyme can thus be improved by making it more heat stable. Another reason could be the effect of the enzyme on the oligosaccharide

concentration in the gut. Interesting research on the use of ABO374 will be the replacement of soybean meal with various levels of sunflower oilcake, reason being that the oligosaccharide concentration of soybean meal is much more than the oligosaccharide concentration found in sunflower oilcake.

3.6 References

Bedford, M. R., 2000. Exogenous enzymes in monogastric nutrition--their current value and future benefits. Anim. Feed Sci. Technol. 86(1-2): 1-13.

Bedford, M. R., 1993. Mode of action of feed enzymes. The Journal of Applied Poultry Research. 2(1):

85.

Bedford, M. R., 2009. The use of NSPases for improving efficiency of nutrient extraction from corn for poultry. Poultry Bulletin. (April): 193.

Bedford, M. R. & Schulze, H., 1998. Exogenous enzymes for pigs and poultry. Nutrition Research Reviews. 11(01): 91-114.

Brufau, J., Francesch, M. & Pérez-Vendrell, A. M., 2001. Are we making the best use of NSP-enzymes? FEED MIX. 9(6): 37.

Choct, M., Hughes, R. J., Trimble, R. P., Angkanaporn, K. & Annison, G., 1995. Non-starch polysaccharide-degrading enzymes increase the performance of broiler chickens fed wheat of low apparent metabolizable energy. J. Nutr. 125(3): 485.

Coon, C. N., Leske, K. L., Akavanichan, O. & Cheng, T. K., 1990. Effect of oligosaccharide-free soybean meal on true metabolizable energy and fiber digestion in adult roosters. Poult. Sci.

69(5): 787-793.

Cowieson, A. J., Hruby, M. & Isaksen, M. F., 2005. The effect of conditioning temperature and exogenous xylanase addition on the viscosity of wheat-based diets and the performance of broiler chickens. Br. Poult. Sci. 46(6): 717-724.

Cowieson, A. J. & Ravindran, V., 2008. Effect of exogenous enzymes in maize-based diets varying in nutrient density for young broilers: Growth performance and digestibility of energy, minerals and amino acids. Br. Poult. Sci. 49(1): 37-44.

Engberg, R. M., Hedemann, M. S., Steenfeldt, S. & Jensen, B. B., 2004. Influence of whole wheat and xylanase on broiler performance and microbial composition and activity in the digestive tract.

Poult. Sci. 83(6): 925.

Esterhuizen, D., 2010. South africa - broiler production and consumption. Retrieved 10/10/2010, http://gain.fas.usda.gov/Recent%20GAIN%20Publications/The%20report%20focus%20on%20br

oiler%20production%20and%20consumption%20_Pretoria_South%20Africa%20-%20Republic%20of_7-28-2010.pdf.

Gous, R. M., 1998. Making progress in the nutrition of broilers. Poult. Sci. 77(1): 111-117.

Hetland, H., Choct, M. & Svihus, B., 2004. Role of insoluble non-starch polysaccharides in poultry nutrition. Worlds Poult. Sci. J. 60(04): 415-422.

Iji, P. A., Khumalo, K., Slippers, S. & Gous, R. M., 2003. Intestinal function and body growth of broiler chickens on diets based on maize dried at different temperatures and supplemented with a microbial enzyme. Reprod. Nutr. Dev. 43(1): 77-90.

Irish, G. G. & Balnave, D., 1993. Non-starch polysaccharides and broiler performance on diets containing soybean meal as the sole protein concentrate. Aust. J. Agric. Res. 44: 1483-1483.

Jackson, M., 2004. Improving soya utilization in monogastrics: Maize-soya diets with β-mannanase.

Feed International. 12: 22-26.

Kidd, M. T., Morgan Jr, G. W., Zumwalt, C. D., Price, C. J., Welch, P. A., Brinkhaus, F. L. & Fontana, E. A., 2001. α-Galactosidase enzyme supplementation to corn and soybean meal broiler diets.

The Journal of Applied Poultry Research. 10(2): 186.

Kleyn, R., 2008. Bio-fuels and agribusiness: Some perspective. Spesfeed (Pty) Ltd. South Africa.

Retrieved 8/10/2010, http://www.spesfeed.co.za/Biofules_and_Agribusiness.pdf

Kleyn, R., 2005. Nutritional strategies and opportunities for the broiler industry in South Africa.

Spesfeed (Pty) Ltd, South Africa, Retrieved 8/10/2010,

http://www.spesfeed.co.za/Nutritional_Stregie_and_Opportunities_for_the_Broiler_Industry_is_S A.pdf.

McNab, J. M. & Boorman, K. N., 2002. Poultry feedstuffs: Supply, composition, and nutritive value.

CABI. London.

Meng, X. & Slominski, B. A., 2005. Nutritive values of corn, soybean meal, canola meal, and peas for broiler chickens as affected by a multicarbohydrase preparation of cell wall degrading enzymes.

Poult. Sci. 84(8): 1242.

Pack, M., Bedford, M. & Wyatt, C., 1998. Feed enzymes may improve corn and sorghum diets.

Feedstuffs. 70(5): 18-19.

Parsippany, N. J., 2008. Non-starch polysaccharide enzymes for poultry. Proceedings of the 6th MID-atlantic nutrition confrence, University of Maryland, 2008.

Pettersson, D. & Åman, P., 2007. Enzyme supplementation of a poultry diet containing rye and wheat. Br. J. Nutr. 62(01): 139-149.

Scott, T. A., 2005. The impact of pelleting and enzyme supplementation on feed value of twenty-five canadian wheat samples. Proceedings of the 17th australian poultry science symposium, 7 February 2005

Silversides, F. G. & Bedford, M. R., 1999. Effect of pelleting temperature on the recovery and efficacy of a xylanase enzyme in wheat-based diets. Poult. Sci. 78(8): 1184.

Shane, S., 1999. What's Your Production Efficiency Factor?: The US broiler industry needs a single numerical factor to compare live-bird performance among flocks. Broiler Industry-Mount Morris.

62(3): 18 -21

Vauqulin, C., 2009. Report of the broiler orginisation committee. South African Poultry Association Wang, Z. R., Qiao, S. Y., Lu, W. Q. & Li, D. F., 2005. Effects of enzyme supplementation on

performance, nutrient digestibility, gastrointestinal morphology, and volatile fatty acid profiles in the hindgut of broilers fed wheat-based diets. Poult. Sci. 84(6): 875.

Zanella, I., Sakomura, N. K., Silversides, F. G., Fiqueirdo, A. & Pack, M., 1999. Effect of enzyme supplementation of broiler diets based on corn and soybeans. Poult. Sci. 78(4): 561.

CHAPTER 4

FIBROLYTIC ENZYMES FOR MAIZE-SOYA DIETS: EFFECTS ON APPARENT DIGESTIBILITY OF NUTRIENTS

4.1 Abstract

A digestibility trial was conducted to compare the digestibility of a maize–soybean meal grower feed containing an experimental enzyme at three levels of inclusion with a negative control, containing no enzyme additions, and a positive control, containing a proven commercial enzyme. The commercial enzyme was a product with a xylanase activity of 38114.29 nkat/g and the second enzyme (ABO374) was a liquid experimental product with a xylanase activity of 1426.86 nkat/ml. Five diets were used i.e. control basal diet without enzyme supplementation (negative control), basal diet supplemented with the commercial enzyme (positive control) and three basal diets supplemented with the test enzyme at various inclusion levels (ABO 50, ABO 100 and ABO 200). The basal diet used in this trial was a grower phase diet. Supplementation with the test enzyme had no significant improvements on the apparent digestibility of dry matter, organic material, ash, crude protein, gross energy or crude fibre. No significant improvements in the apparent digestibility of the amino acids (threonine, arginine, valine, lysine, methionine, cysteine and isoleucine) were noticed and thus the digestibility of the grower feed was not influenced by the addition of enzymes due to the supplementation of the test enzyme ABO374.

Key words: apparent digestibility, dry matter, organic material, ash, crude protein, gross energy, crude fibre, xylanase, maize, soybean meal

4.2 Introduction

A significant part of all plant feedstuffs are made up by dietary fibre (Hetland et al., 2004). The soluble dietary fibre fraction however has anti-nutritive effects in poultry (Bedford, 1993; Bedford, 1996;

Knudsen, 1997; Bedford & Schulze, 1998; Bedford, 2000; Hetland et al., 2004; Jørgensen et al., 2007). These non-starch polysaccharides (NSP) increase gut viscosity and thereby inhibit digestion and absorption of nutrients (Bedford, 1993). The increase in gut viscosity also reduces feed intake due to a slower feed passage rate, which leads to the proliferation of microbes in the gut (Hetland et al., 2004). The negative correlation between the NSP content of feed and the nutritive value of the feed has been clearly demonstrated in poultry and this has led to the enormous attention that the fibre component of poultry feed has received in recent years (Bedford, 1993; Bedford & Schulze, 1998;

Bedford, 2000; McNab & Boorman, 2002).

Non-starch polysaccharides mostly present in raw materials used for poultry diets are pectins, cellulose, mixed-linked β-glucans and arabinoxylans (Parsippany, 2008). Depolymerisation of these NSPs requires specific enzymes, which are specific to the main and side chain structure of the NSP (Bedford, 1993; Henry & Rothwell, 1995; Castanon et al., 1997; Bedford & Schulze, 1998; Bhat, 2000;

Andersson et al., 2003; Dalibard & Geraert, 2004).

The application of exogenous fibrolytic enzymes in the poultry industry have been used to neutralise the anti-nutritive effects of NSPs present in wheat, barley, rye and oats and this has proven to be a successful means of improving broiler production performance and feed digestibility (Choct et al., 1995; Brufau et al., 2001; Engberg et al., 2004; Cowieson et al., 2005; Scott, 2005; Wang et al., 2005;

Pettersson & Åman, 2007). The use of NSP-degrading enzymes in wheat and barley based diets for broilers are therefore well established and accepted (McNab & Boorman, 2002; Bedford, 2009). The role of fibrolytic enzymes in broiler diets based on raw materials with substantially lower concentration of NSPs are yet to be proven, although various studies have concluded that maize and soybean meal based diets are responsive to supplemental fibrolytic enzymes (Cowieson & Ravindran, 2008).

The objective of this trial was to compare the digestibility of a basal grower diet containing three different activity levels of an experimental xylanase product with that of a negative control receiving no exogenous fibrolytic enzymes and a positive control receiving a proven commercial xylanase exogenous enzyme.

4.3 Materials and methods

Four hundred and eighty Cobb 500 chicks at one day-old (as hatch) were bought from a commercial hatchery and grown to the age of 21 days on the starter diet presented in Table 22. The birds were housed in an environmentally controlled house, the temperature and lighting was managed according to the specifications of the primary breeder. The environmental temperature of the house for the first day was 33˚C and was decreased by 2˚C every seventh day to 20˚C at 35 days of age. A minimum of six air changes per minute was provided for the birds. The birds had ad libitum access to feed and water.

At 21 days of age, the chicks were placed in individual metabolic cages. All the metabolic cages were equipped with feeders, automatic water nipples and faeces collection trays. The trial was conducted in an environmentally controlled house, the temperature and lighting was managed according to the specifications of the primary breeder.

Table 21 A description of the dietary treatments used throughout the trial Treatment Description

Negative control Control diet

Positive control Control diet + Commercial enzyme (7622858 nkat/ton of feed) ABO 50 Control diet + ABO374 (3811429 nkat/ton of feed)

ABO 100 Control diet + ABO374 (7622858 nkat/ton of feed) ABO 200 Control diet + ABO374 (15245716 nkat/ton of feed)

The trail consisted of three treatments, a negative control and a positive control group. A grower diet according to the nutrient specifications of the primary breeder was formulated using the feed formulation program Winfeed and fed to the birds (Table 22). The grower diet was fed as pellets.

A commercial enzyme product was added to the positive control diet at the manufacturer’s recommendations of 200 g/ton. The commercial enzyme product was added to the diet in a granular form. The test product, ABO374, was added to the diets of ABO 50, ABO 100 and ABO 200 at various inclusion levels in liquid form. The inclusion level of ABO374 is 5342 ml/ton as determined by the Department of Microbiology at the Stellenbosch University. The inclusion level of ABO374 was determined so that the xylanase activity of the commercial enzyme and ABO374 are the same in the feed. The xylanse activity of the commercial enzyme and ABO374 determined by Department of Microbiology at the Stellenbosch University were 38114.29 nkat/g and 1426.86 nkat/ml respectively.

ABO 50 was supplemented with ABO374 at an inclusion level of 2671 ml/ton, ABO 100 with 5342 ml/ton and ABO 200 with 10684 ml/ton. There was no enzyme supplementation in the negative control diet. Pelleting of feed took place 24 hours after enzyme addition of application. Cellulose in the form of powder was added to diets to replace the granular enzyme on a weight for weight basis while water was added to diets to replace liquid enzyme additions on a weight for weight basis. These additions are shown in Table 23.

The total tract digestibility method and total collection method was used to conduct the digestibility trial. The total tract digestibility method measures the difference between the amounts of each nutrient consumed from the amounts of each nutrient excreted in faeces. The grower negative control, positive control, ABO 50, ABO 100 and ABO 200 diets used in the production trial were also used in the digestibility trial.

Each treatment in this digestibility trial consisted of a total of twenty 21 day old broilers. The birds were subjected to 100% ad libitum feed intake. The first four days were used for adaptation. During the adaptation period the treatment feeds, to which the broilers were allocated, were fed ad lib. Feed intake was measured for each individual bird during the adaption period to determine the amount of feed taken in per day. The measurements were then used to calculate the amount of feed that each individual bird had to receive during the trial.

The trial s

Table 22 Ingredient and calculated nutrient composition of the broiler diets used in the digestibility trial on an as fed basis (g/kg)

Starter Grower

Ingredient (g/kg)

Maize 498.73 503.75

Soybean full fat 420.63 289.91

Soybean 46 33.61 164.11

L-lysine HCl 3.66 1.16

DL-methionine 2.32 1.52

L-threonine 1.29

Limestone 16.60 16.61

Salt 2.13 2.47

Monocalcium phosphate 16.41 16.39

Sodium bicarbonate 2.11 1.58

Vitamin + mineral premix * 1.50 1.50

Methionine+Cystine (%) 0.93 0.88

Threonine (%) 0.97 0.88

Phenylalanine+Tyrosine (%) 1.79 1.92

Valine (%) 1.08 1.15

Available Phosphorous (%) 0.50 0.50

Sodium (%) 0.16 0.16

Chloride (%) 0.22 0.22

Potassium (%) 0.91 0.97

Linoleic acid (%) 5.20 4.02

Choline (mg/kg) 1606.13 1600.00

*Vitamin+mineral premix provides (per kg of diet): 8160 Iu Vitamin A, 1700 Iu Vitamin D3, 30.6 Iu Vitamin E, 2.7 mg Vitamin K3, 2.05 mg Vitamin B1, 2.05 mg Vitamin B2, 27.2 mg Niacin, 10.2 mg Calcium Pantothenate, 0.02 mg Vitamin B12, 4.1 mg Vitamin B6, 1.7 mg Folic acid, 0.068 mg Biotin, 0.08 mg Iodine, 0.34 mg Cobalt, 0.2 mg Selenium, 120 mg Ronozyme p500, 350 mg Choline, 70 mg Manganese, 70 mg Zinc, 6 mg Copper and 50 mg Ferrous

Table 23 Amount of added water, cellulose and enzyme to the different treatments

Ingredient

Treatments Negative

control

Positvie

control ABO 50 ABO 100 ABO 200

Water (ml/ton) 10684 10684 8013 5342 0

Cellulose (g/ton) 200 0 200 200 200

Commercial enzyme (g/ton) 0 200 0 0 0

ABO374 (ml/ton) 0 0 2671 5342 10684

4.4 Results and discussion

The mean apparent digestibility coefficients for the nutrients in the broiler chickens fed by dietary treatments at 100 % ad libitum are shown in Table 24. The apparent dry matter digestibility of 80 % for the negative control was significantly (P<0.05) higher than those of the ABO 50, ABO 100 and ABO 200 diets, with apparent dry matter digestibilities of 75 %, 75 % and 72 % respectively. Apparent digestibility for dry matter of the positive control (78 %) was also significantly higher (P<0.05) than those of the ABO 50, ABO 100 and ABO 200 diets. Significant differences (P<0.05) between the negative control and ABO 100 and ABO 200 apparent ash digestibility was observed. The apparent digestibility of ash for the negative control was 44 %, for ABO 100 it was 31 % and for ABO 200 it was 29 %. Apparent ash digestibility of the positive control (43 %) and ABO 50 (42 %) was also significantly higher (P<0.05) than the apparent ash digestibilities of ABO 100 and ABO 200. The apparent digestibility for organic matter of ABO 50 (77 %), ABO 100 (78 %) and ABO 200 (76 %) was significant lower (P<0.05) than that of the negative control (82%). ABO 50 and ABO 100 had significant higher (P<0.05) apparent digestibility for organic matter than ABO 200. Supplementation with the ABO374 enzyme did not result in any improvement in the apparent metabolisable energy.

The apparent gross energy digestibility for the negative control (83 %) was significantly higher (P<0.05) than those of the ABO 50 (79 %), ABO 100 (81 %) and ABO 200 (77 %) diets. ABO 100 had a significant higher (P<0.05) apparent digestibility than ABO 200.

The apparent crude protein digestibility of the negative control (73 %) was significantly higher than those of the positive control (67 %), ABO 50 (65 %), ABO 100 (64 %) and ABO 200 (59 %) diets. ABO 200 had a significantly lower (P<0.05) apparent crude protein digestibility than the positive control, ABO 50 and ABO 100 diets. The positive control and ABO 50 diets had significant lower (P<0.05) apparent crude fibre digestibilities than the negative control, ABO 100 and ABO 200 diets. The positive control had an apparent crude fibre digestibility that was significantly higher (P<0.05) than that of the ABO 50 diet. The negative control, positive control, ABO 50, ABO 100 and ABO 200 had apparent crude fibre digestibilities of 45 %, 35 %, 21 %, 43 % and 37 % respectively.

Table 24 Mean apparent digestibility coefficients of nutrients in broiler chickens receiving diets containing no enzyme addition, commercial enzyme or three inclusion levels of test enzyme

Negative control  0.80^a  0.44^a 0.82^a 0.83^a 0.73^a  0.45^a

Positive control  0.78^a  0.43^a 0.81^ab   0.82^ab 0.67^b  0.35^c

ABO  50  0.75^bc  0.42^a 0.77^cd   0.79^cd 0.65^b  0.21^b

ABO 100  0.75^b  0.31^b 0.78^bc   0.81^bd 0.64^b  0.43^ad

ABO  200  0.72^c  0.29^b 0.76^d 0.77^c 0.59^c  0.37^ad

a – d

Means within a column with common superscripts are not significantly different (P<0.05)

The mean apparent digestibility coefficients for the individual amino acids in the broiler chickens fed the dietary treatments at 100 % ad libitum are shown in Table 25. Enzyme supplementation with ABO374 did not result in any improvements in the apparent digestibilities of any amino acids. The apparent digestibility for threonine, arginine, valine, lysine, methionine, cysteine and isoleucine for the negative control diet was all significantly higher (P<0.05) than the positive control, ABO 50, ABO 100 and ABO 200 diets.

Table 25 Apparent total tract digestibility coefficients for individual amino acids in broiler chickens receiving diets containing no enzyme addition, commercial enzyme or three inclusion levels of test enzyme

Treatments  Threonine  Arginine  Valine  Lysine  Methionine  Cysteine  Isoleucine  Negative control  0.97^a  0.97^a    0.93^a  0.96^a  0.98^a  0.94^a  0.97^a 

Means within a column with common superscripts are not significantly different (P>0.05)

The findings in this digestibility trial in regard of the individual apparent amino acid digestibility are not in agreement with the results found by other researchers who conducted the same type of trials (Pack et al., 1998; Zanella et al., 1999; Kidd et al., 2001; Iji et al., 2003; Jackson, 2004; Cowieson &

Ravindran, 2008). According to Irish & Balnave (1993), oligosaccharides cannot be broken down in the broiler’s intestine due to the absence α-galactosidase activity.

When the concentration of oligosaccharides in the bird’s small intestine is high, it produces an osmotic effect. This leads to fluid retention and increases the feed passage rate, which in turn leads to a negative effect on nutrient absorption (Irish & Balnave, 1993).

A possible reason why enzyme supplementation did not increase nutrient digestibility may be that the breakdown of non-starch polysaccharides by the enzymes led to an increase in the concentration of oligosaccharides in the small intestine of the birds, thus leading to the decrease in nutrient absorption (Irish & Balnave, 1993). Coon et al. (1990) conducted a study where they removed the oligosaccharides from soybean meal by means of ethanol. The ethanol-extracted soybean meal was then fed to broilers to determine the nutritional differences due to the removal of the oligosaccharides.

They found a significant (P<0.05) increase in fibre digestibility and in the metabolisable energy value, this response was attributed to a decrease in feed passage rate and thus an increase in nutrient absorption (Coon et al., 1990). The commercial enzyme and ABO374 used in this trial was only analysed for xylanase activity and not for proteolytic activities and therefore we do not know if they have any proteolytic activities. Looking at the results for individual apparent amino acid digestibility, it may be possible that the enzymes used in this trial have no proteolytic activity. This may be another possible reason why no significant improvements in individual apparent amino acid digestibility were found. Researchers who found significant improvements in amino acid digestibility due to enzyme supplementation, have all reported that enzymes used by them had proteolytic activity (Zanella et al., 1999; Kocher et al., 2002; Meng & Slominski, 2005).

4.5 Conclusion

The objective of this trial was to determine whether an experimental xylanase enzyme (ABO374) product had the potential to increase the digestibility of a broiler feed based on maize and soybean meal as the main protein source. The experimental xylanase enzyme (ABO374) product was also compared to a commercial xylanase enzyme product.

According to the results obtained during this digestibility trial, ABO374 did not improve the apparent digestibility of a commercial maize- soybean meal based grower diet. However, these results cannot

According to the results obtained during this digestibility trial, ABO374 did not improve the apparent digestibility of a commercial maize- soybean meal based grower diet. However, these results cannot

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